Valve



Sept. 30, 1969 G, F, SEKERA, JR 3,469,781

VALVE Filed Fen-'21; 1968 \32 MAIN BURNER CONTROL I/V VENTOR:

' GEORGE SEKERA, JR. By,-

CM/ILM,

United States Patent O 3,469,781 VALVE George F. Sekera, Jr., Hinsdale, Ill., assignor to Harper- Wyman Company, Hinsdale, Ill., a corporation of Illinois Filed Feb. 21, 1968, Ser. No. 707,210 Int. Cl. F23n 5/06 U.S. Cl. 236-99 6 Claims ABSTRACT F THE DISCLOSURE A safety valve for controlling the admission of gas to a burner in accordance with the, existence of a sensed condition includes a housing having opposed side Walls and having a valve and a power element movable in response to presence or absence of the sensed condition. A pair of pivot pins extend inwa-rdly from the side walls and have spaced ends permitting the power element to be positioned between the pins. An operating lever extends between the power element and the valve and is pivotally mounted by a pair of disengageable hooks pivotally engaging the pins. An adjustment member carried by the lever is in point contact with a flat on the power element so that the relatively short effective lever arm distance between the pivot axis and the point of application of force is fixed. The adjustment member when moved to its adjusted position locks the lever in place.

The present invention relates to valves, and more particularly to a new and improved safety valve or burn-er valve which has few parts, is easy to assemble and has improved operating characteristics.

Valves referred to as burner valves or safety valves are widely used in gas ovens and other appliances for controlling gas flow to a main burner in response to a sensed condition such as the presence or absence of a flame indication at a pilot burner. One type of valve includes a power element which may be mounted on an expansible diaphragm or other condition responsive means and which is movable between positions depending upon the presence or absence of the sensed condition. A valve is moved between a closed and a fully open position in response to movement of the power element by means of a lever pivotally mounted in the valve housing.

IIn such arrangements the power element ordinarily moves a short distance while the valve must be moved a substantially greater distance between its open and closed positions. Consequently, the lever arm pivot axis is located close to the power element and farther from the valve. Known safety valves have been expensive to manufacture due to the close tolerances necessary for manufacturing and locating the power element and the lever supporting means in order to maintain the effective lever arm distance between the pivot axis and the power element within a desired range. Despite such efforts, however, known valves are subject to the difficulties encountered due to the effective lever arm distance being too long or too short-these difficulties including premature failure of the expansible diaphragm and failure of the valve to open fully. Other disadvantages to which known valves are subject include complexity and difficulty in assembly.

Accordingly, it is an important object of the present invention to provide an improved safety valve or burner valve and to overcome the above and other disadvantages of known valves.

A further object is to provide an improved safety valve which is simple, compact and easily assembled.

Another object of the present invention is to provide an improved safety valve in which the effective lever arm distance between the pivot axis and the point of application of force is fixed with respect to the lever arm without the necessity of maintaining critical tolerances.

A further object is to provide a safety valve in which the expansible diaphragm is not subject to excessive force and in which the valve opens fully.

Another object is to provide a novel safety valve construction wherein the pivotally mounted operating lever is latched or held in position upon adjustment of the assembled valve.

In brief, in accordance with the above and other objects of the invention one embodiment of the invention may comprise a safety valve or burner valve including a housing supporting a valve and a power element movable between positions. A pivotally mounted lever extends between the valve and the power element for opening and closing the valve in response to movement of the power element. In accordance with one feature of the invention, the effective lever arm distance between the point of application of force to the lever by the power element and the pivotal axis of the lever is fixed by the construction of the lever, and is not dependent on the position of the lever mounting means or on the position of the power element.

Another feature of the invention resides in the simplicity and compactness of the valve. The lever is pivotally mounted on pin means supported on the valve housing so that the need for a separate support bracket or the like is avoided. In addition, a pair of short pins having spaced inner ends are used, and the power element is disposed in a compact arrangement between the spaced inner ends.

'In accordance with a further feature of the invention, the assembly of the safety valve is greatly simplified. Thus the lever is provided with hooks releasably and pivotally engaging the pins, and in assembly the lever is merely hooked into place. In addition, upon :adjustment of the safety valve the lever is locked into position by an adjustable member engageable with the power element.

The invention, together with the above and other objects and advantages, may be better understood from consideration of the following detailed description of one embodiment of the invention illustrated in the accompanying drawing in which:

FIG. 1 is a perspective view of a safety valve constructed in accordance with the present invention, portions being broken away more clearly to illustrate the valve;

FIG. 2 is an elevational view of the valve with the cover removed;

FIG. 3 is a sectional view taken along the line 3 3 of FIG. 2 together with a diagrammatic illustration of one system in which the valve may be utilized; and

FIG. 4 is an enlarged, fragmentary sectional view taken along the line 4-4 of FIG. 2.

Referring now to the drawing, there is illustrated a safety valve or burner valve constructed in accordance with the principles of the present invention and designated as a whole by the reference numeral 10. In general, the valve 10 includes a housing 12 provided with an inlet 14 and an outlet 16 in communication with one another by way of a valve seat 18 supported in the housing. Flow through the valve seat 18 between the inlet -14 and the outlet 16 is controlled in accordance with a sensed condition by a valve member 20. A power element 22 moves between positions in accordance with the sensed condition, and a pivotally mounted lever 24 moves the valve member 20 between open and closed positions in response to movement of the power element 22.

Referring to FIG. 3, there is diagrammatically illustrated one system with which the valve 10 of the present invention may be used. As there illustrated, the inlet 14 of the valve is supplied with fuel from a suitable control 26 such as a shutoff valve and/or thermostatically controlled valve or the like, while the outlet 16 of the valve 10 is communicated with a main burner 28. The system includes a pilot burner 30 supplied from the control 26 and located adjacent the main burner for igniting the main burner. The valve 1t)` functions to admit gas to the main burner only when a temperature sensing means 32 disposed adjacent the pilot burner is heated by a flame at the pilot burner. Heating of the means 32 results in movement of the power element 22 whereupon the lever 24 pivots and moves the valve member 20 away from the seat 18 to establish communication between the inlet 14 and the outlet 16 thereby to permit fuel to flow to the burner 28. The system of FIG. 3 is described for purposes of illustration only, and the valve 10 could be used in other types of systems as well.

Proceeding to a more complete description of the valve 10, the housing 12 includes a pair of opposed side walls 12a and 12b and an open wall closed by a cover 34 (FIG. l) after assembly of the valve. Fuel entering the inlet 14 flows through a passageway 36 into a chamber 38 comprising a cylindrical bore bounded at one end by the valve seat l18 and closed at the other end by a plug member `40. When the valve member 2t) is in the open position gas flows through the seat 18 into an outlet chamber 42 and flows through an outlet fitting 44 at the outlet 16. For purposes of convenience and clarity the valve 1i) is illustrated in the drawings in what might be termed an upside down position. Although the valve could be installed in any orientation, in many installations the fitting 44 may discharge fuel upwardly through an adjustable orifice and into a vertically extending inlet portion of a main burner.

The condition sensitive assembly of the valve 10 may be of any desired type known to those skilled in the art. As illustrated, the power element 22 is supported above an expansible diaphragm 46 composed of a pair of intertting cup-shaped flexible members 46a and 46b (FIG. 4) sealed together at their edges. The interior of the diaphragm communicates by way of a capillary tube 48 with the temperature sensing means 32 which comprises a hollow bulb or the like. The bulb, capillary and diaphragm are charged with an expansible duid such as mercury through a filling opening in a platform 50, which opening is subsequently closed by a sealing element 52.

In order to translate expansion of the diaphragm 46 into pivotal movement of the lever 24, the power element 22 is supported on the platform 50 to move upwardly and downwardly as illustrated in the drawing as the diaphragm expands and contracts. Advantageously the element 22 includes a raised central portion 22a defining a chamber 54 enclosing the sealing element 52 so that the sealing element is not subjected to the forces transmitted by the power element. A depending portion 22h of the power element locates the power element on the platform 50 and also holds a spring 55 in compression between the power element and the lever 24.

In order normally to hold the valve member 2t) against the seat 18 and prevent flow through the valve in the absence of expansion of the diaphragm 46, a spring 56 (FIG. 3) is held in compression between the valve member and the plug member `40. Upon expansion of the diaphragm 46 the power element 22 moves upwardly as illustrated in the drawing from the illustrated position to an alternate position, and the lever 24 is pivoted in a counterclockwise direction as illustrated in the drawing in order to open the valve. A motion transmitting member 58 engages the valve member 20 and an overtravel spring 60 permits the lever 24 to continue to move after the valve member 20 reaches its fully open position.

One important aspect of the present invention is the simplicity and compactness of the valve 10. In order pivotally to mount the lever 24, a pair of pivot pins 62 and 64 extend inwardly from the side walls 12a and 12b of the housing 12 along a line between the side walls, which line comprises the pivot axis of the lever 24. Accordingly, the necessity for additional structure such as a lever supporting bracket or the like is avoided. In the illustrated embodiment the pins 62 and 64 are seated in holes drilled through the side walls 12a and 12b. If desired, however, the pins could be integral with the housing.

In order to permit the elements of the valve 10 to be arranged in a compact and convenient fashion, the inwardly directed ends of the pins 62 and 64 are spaced from one another. As appears most clearly in FIGS. 2 and 3, the power element 22 occupies the space between the ends of the pins 62 and 64.

The assembly of the safety valve 10 is greatly simplified due to the fact that the lever 24 can easily be placed into position. Thus the lever includes a pair of hooks 66 and 68 at opposite sides of the lever and engageable with the pins 62 and 64. In assembly of the device the lever 24 is merely dropped into place and the hooks `66 and 68 are hooked around the pins 62 and 64. When the lever is in place, it pivots freely about the pins 62 and 64. Furthermore, the hooks are releasable from the pins in order to facilitate repair or replacement of parts of the valve 10.

Since the movement of the power element is slight compared to the distance through which the valve 20 must move between its closed and fully opened positions, the point of application of force to the lever 24 is necessarily close to the pivot axis of the lever. Furthermore, it is important accurately to control the effective lever arm distance between the pivot axis and the point of application of force. In many prior art arrangements the position of the pivot axis has depended upon the position of pivot members supported on structure other than the lever. In addition, the position of application of force has depended upon the placement of the power element with respect to the housing. It has been necessary to maintain close tolerances in the manufacture of prior art valves in order to maintain the effective lever arm distance within the desired range. If the lever arm distance is too short, the force exerted against the diaphragm in operation of the device increases to the extent that premature diaphragm failure is caused by fatigue of the metal of the diaphragm walls. On the other hand, if the effective lever arm distance is too long the valve does not open fully and the gas flow through the valve is decreased. In addition, variations in the lever arm length bring about Variations in the pressure to which the fluid within the temperature sensing system is subjected. Such pressure variations influence the temperature at which the uid vaporizes, and in some valve installations this temperature may be important.

In order to overcome this problem, and in accordance with an important feature of the invention, the valve 10 is provided with a novel arrangement for assuring that this effective lever arm distance is fixed without the necessity for maintaining close tolerances in the construction of the housing and other structure. This is accomplished in accordance with the invention by providing a construction wherein both the pivot axis of the lever and the point of application of force to the lever are determined by construction of the lever and are not dependent upon the position of other parts of the valve assembly. Since the effective lever arm distance is determined by the construction of the lever, it is not necessary to maintain close tolerances in constructing and in positioning other elements of the valve assembly.

More specifically, the pivot axis about which the lever rotates in operation is determined with respect to the lever by the positions of the hooks 66 and 68. In other words, the point along the lever at which the pivot axis exists does not depend upon the positions of the pins 62 and 64 or other lever mounting structure, and if the hooks 66 and 68 are properly positioned along the length of the lever, the pivot axis will also lbe properly positioned.

In addition, the point of application of force to the lever `by the power element 22 is also fixed by the construction of the lever. The lever 24 is coupled to the power element 22 through the medium of an adjustment screw 70 threaded into an opening 72 in the lever. Referring more particularly to FIG. 4, it can be seen that the lower end of the adjustment screw is provided with a small curved or spherical abutment 74 which makes substantially point contact with a flat surface 22C of the power element 22. Accordingly, regardless of the exact positioning of the power element 22 or diaphragm 26, the point of application of force to the lever 24 is the point at which the abutment 74 engages the flat surface 22cthis point being determined by the positioning of the hole 72 in the lever 24. Furthermore, there is no problem of the lever 24 binding if the structure of the valve is not precisely positioned.

The effective lever arm distance between the pivot axis and the point of application of force in the valve is accordingly determined by the construction of the lever 24, and specifically by the positioning of the hooks 66 and 68 and the hole 72. Since only these two factors are involved the lever arm, and other valve structure, can be manufactured with relatively open tolerances and therefore inexpensively without the problems encountered when the effective lever arm distance is not in the desired range.

Another important feature of the present invention is that the lever 24 is locked or held in position when the valve is assembled and adjusted for operation. When the lever 24 is hooked into place on the pins 62 and 64 as described above, the adjustment screw 70 is in a retracted position or is not yet in place in the lever arm. When the assembly is completed the adjustment screw 70 is moved or extended with respect to the lever arm toward the power element 22 to the position illustrated in the drawings. This position may be referred to as a properly adjusted position or an operating position, and in this position the abutment 74 engages the liat 22c on the power element 22 and the valve 20 is seated against the valve seat 18.

In this properly adjusted or operating position of the adjustment screw 70, the lever arm 24 cannot be removed from the valve assembly because interference between the screw 70 and the power element 22 prevents the lever from being moved downwardly as illustrated in the drawings to a position wherein hooks y66 and 68 can be disengaged from the pins 62 and 64. Accordingly, the lever 24 is retained in position until such time as the adjustment screw 70 is moved to a retracted position or is removed and the lever arm cannot become disengaged during shipment or installation.

While the present invention has been described with reference to details of a particular embodiment, many other modifications and embodiments may be devised by those skilled in the art. Details of the described embodiment of the invention are not intended to limit the scope of the invention as defined in the following claims. For example, the principles of the present invention could be applied to another type of safety valve wherein a single valve member controls ow through a pair of outlets in dependence upon presence or absence of a llame indication at a pilot burner.

What is claimed and desired to be secured by Letters Patent of the United States is:

1. A safety valve comprising a housing having opposed side walls and an open wall, a valve means and a power element mounted at spaced positions in said housing, pivot pin means fixed to opposed points on said side walls and extending along a line between said side walls, said pivot pin means comprising a pair of pins each extending inwardly from one of said side walls and having spaced inner ends, a lever insertable into said housing through said open wall and having spaced portions operatively connected to said valve means and to said power element for operating said valve means in response to movement of said power element, and hook means on said lever pivotally and releasably engageable with said pin means, saidpower element including a portion disposed along said line between said side walls and between said spaced ends of said pins.

2. The safety valve of claim 1, said hook means comprising a pair of hooks adjacent opposite sides of said lever, each engageable with one of said pins.

3'. The safety valve of claim 2, an adjustable membel movably mounted on said lever and engageable with said power element, said adjustable member being movable with respect to said lever to a position in which said hooks cannot be removed from said pins.

4. A safety valve comprising a housing having opposed sidewalls and an open wall, a valve means and a power element mounted at spaced positions in said housing, pivot pin means xed to opposed points on said side walls and extending along a line between said side walls, a lever insertable into said housing through said open wall and having spaced portions operatively connected to said valve means and to said power element for operating said valve means in response to movement of said power element, hook means on said lever pivotally and releasably engageable with said pin means, and an adjustable member on said lever movable to a retracted position in which said hook means can be engaged with said pin means, said adjustable member being movable to an operating position wherein the valve is adjusted for operation and wherein said adjustable means engages said power element, said adjustable means preventing removal of said hook means from said pin means in said operating position.

5. A safety valve comprising a housing having spaced side walls, a valve means in said housing and movable between closed and open positions, a lever engageable with said valve means for moving said valve means between positions, a pair of pivot pins each extending inwardly from one of said side walls and having spaced inner ends, said lever being pivotally mounted on said pivot pins, and power means movable in response to changes in a sensed condition, said power means being supported in said housing directly between the spaced ends of said pivot pins and being engageable lwith said lever.

6. A safety valve as deiined in claim 5, said pivot pins being seated in holes formed in said side walls.

References Cited UNITED STATES PATENTS 1,477,277 12/1923 Milker.

2,924,388 2/1960 Beck et al 236-99 3,213,922 10/1965 Weber 236-99 X 3,251,573 5/1966 Miller et al 251-58 X WILLIAM E. WAYNER, Primary Examiner U.S. C1. X.R. 74-519; 251-58; 337-327 

